New US Passive House Standard debuts
After three years of development the Passive House standard for North America is now available.
Originally developed in Germany, the Passive House building standard has been gaining ground in North America, but many building professionals felt it did not offer enough flexibility for the diverse climate zones in the United States for example.
The goal of Passive House is to build a very tight building envelope and use design elements to dramatically reduce air leakage and the need for mechanical heating by employing performance-based criteria and maximizing cost-effective savings from conservation.
Now, after nearly three years in the works, peer review from the U.S. DOE and public comments, the PHIUS+ 2015: Passive Building Standard--North America is here.
According to an announcement from the Passive House Institute US, the "new standard provides the sweet spot where aggressive energy and carbon reduction overlap with cost effectiveness." The standards take into account a full range of variables including climate zone, source energy, and costs. The effort is the product of a partnership of the PHIUS Technical Committee and Building Science Corporation (BSC) under a U.S. DOE Building America Grant. (The final U.S. DOE Report is downloadable from the BSC site.)
Go here to Find the new performance targets for your climate on the PHIUS+ 2015 interactive map -- and learn more about the development of the standard, what's different and what's not.
The PHIUS+ project certification process and documentation have been updated to reflect the new performance metrics. Users can download the updated certification documents from the Getting Started box on the PHIUS+ Registration page.
The new standard were announced at the PHIUS 2105 launch event March 25, 2015, in Seattle as part of the annual Passive House Northwest conference. PHIUS Executive Director Katrin Klingenberg provided an overview of the impetus for the new standard, as well as a capsule summary of what’s new and what’s better.
Passive House Institute and the U.S. Department of Energy collaborated on the new standards to reflect climate zones and realistic building costs, according to these excerpts from the Executive Summary of the Climate Specific Building Standards.
In 2012, the United States Department of Energy (DOE) recognized the value of performance based passive building standards when it joined with Passive House Institute US (PHIUS) to promote DOE’s Challenge Home program in tandem with the PHIUS+ passive house certification program. Since then, the number of passive building projects certified under the partnership has grown exponentially.
This is due to some synergy: passive building represents a well-developed approach to arrive at the envelope basis for Net Zero and Net Positive projects by employing performance-based criteria and maximizing cost-effective savings from conservation first. The Zero Energy Ready Home (ZERH) program evolved from the Challenge Home program in a move toward attaining zero energy and including active energy generation—like photovoltaics—toward that goal.
A synthesis of the two programs, PHIUS+ and ZERH – combining optimized performance-based envelope design guidelines and zero energy goals – has the potential to make Net Zero a mainstream market force. But experience to date has identified a critical obstacle to wide-scale adoption across the nation: The passive/conservation performance metric currently used as the envelope design guideline for space conditioning criteria (following the German Passivhaus Standard) is not responsive to the wide diversity of climate and energy market conditions in the United States.
A volunteer technical expert advisory council, the PHIUS Technical Committee (TC) has assisted the authors in the process and the results reflect consensus votes by this volunteer expert body. The main guiding criteria comprise three “pillars”: space conditioning criteria (that is, limits on heating and cooling loads) that incent passive measures, a source energy criterion incenting efficient use of equipment and meeting environmentally-required reduction targets with “conservation first”, and an air-tightness criterion to assure that highly-insulated envelopes do not develop moisture problems that will lead to significant failures of the envelope components.
In summary, adaptations are proposed for all three pillars:
By its structure, the proposed standard has the feature of “three hurdles to net zero source.” The designer’s attention is directed first to reducing heating and cooling energy use by passive means (including some mechanical devices), then to reducing total energy demand by efficient equipment (and some renewables), and finally to source-net-zero by more renewable generation.
Read more about passive house building.